Building automation systems encompass a wide variety of systems that aid in the monitoring and control of various aspects of building operation. Building automation systems include security systems, fire safety systems, lighting systems, and HVAC systems. The elements of a building automation system are widely dispersed throughout a facility. For example, an HVAC system may include temperature sensors and ventilation damper controls, as well as other elements, that are located in virtually every area of a facility. These building automation systems typically have one or more centralized control stations from which system data may be monitored and various aspects of system operation may be controlled and/or monitored.
To allow for monitoring and control of the dispersed control system elements, building automation systems often employ multi-level communication networks to communicate operational and/or alarm information between operating elements, such as sensors and actuators, and the centralized control station. One example of a building automation system is the Site Controls Controller, available from Siemens Industry, Inc. Building Technologies Division of Buffalo Grove, Ill. (“Siemens”). In this system, several control stations connected via an Ethernet or another type of network may be distributed throughout one or more building locations, each having the ability to monitor and control system operation.
Maintaining indoor air quality in commercial buildings requires that significant outside (fresh) air be supplied according to building codes and industry standards. Most retail sites have HVAC systems set up statically to serve maximum occupancy levels. As buildings are rarely fully occupied, the HVAC system wastes energy heating, cooling, and dehumidifying this excess amount of outside air. In many applications, the HVAC fan is programmed to run 24/7, regardless of heating or cooling need, or occupancy levels, further wasting energy.
Household and small-business HVAC systems have similar issues with inefficient heating, cooling, or ventilation when such operations are not needed by the homeowner or occupant.